Boosting oxygen reduction of well-dispersed CoP/V(PO3)3 sites via geometric and electronic engineering for flexible Zn–air batteries

Abstract

Possessing electron-rich phosphorus and metal sites, transition metal phosphides are expected to break through the reaction kinetics barrier of the oxygen reduction reaction (ORR) for Zn–air batteries (ZABs). Herein, well-dispersed CoP/V(PO₃)₃ heterojunction nanoparticles were decorated on hollow carbon spheres (CoP/V(PO₃)₃@HCS) via bi-surfactant template tactics. Experimental and theoretical investigations synergistically confirmed that multi-component coupling induced a charge redistribution and a moderate d-band center, which optimized the adsorption of intermediates and activation energy barrier. Because of the above features, the resultant CoP/V(PO₃)₃@HCS exhibits eminent ORR activity (E_1/2 = 0.81 V, j_L = 5.6 mA cm⁻²) and stability (10 h, ∼98%), surpassing those of most previous reports. Impressively, a CoP/V(PO₃)₃@HCS-based aqueous ZAB achieves a high power density (182 mW cm⁻²) and an extremely long life (710 h), being 1.4 and 1.6 times those of the commercial Pt/C, respectively, and its assembled flexible counterpart features extraordinary bending stability.